Emily Dickinson Lexicon

PRIN'CI-PAL, a. [Fr. from L. principalis, from princeps.]

1. Chief; highest in rank, character or respectability; as, the principal officers of a government; the principal men of a city, town or state. – Acts xxv. 1 Chron. xxiv.
2. Chief; most important or considerable; as, the principal topics of debate; the principal arguments in a case; the principal points of law; the principal beams of a building; the principal productions of a country. Wisdom is the principal thing. – Prov. iv.
3. In law, at principal challenge, is where the cause assigned carries with it prima facie evidence of partiality, favor or malice. – Blackstone.
4. In music, fundamental.